Washing machine appliances can clean articles disposed therein using steam. Steam can increase certain wash cycles' efficiency and effectiveness. For example, steam can decrease the amount of time and/or water needed to clean articles. Also, steam can assist in reducing wrinkles or odors in articles cleaned by such washing machine appliances.
To generate steam, certain washing machines appliances include a steam generator in which steam is generated and subsequently piped to a wash chamber of the appliance. Alternatively certain horizontal axis washing machine appliances generate steam within the appliance's wash chamber. However, currently, certain challenges exist to the use of steam in vertical axis washing machine appliances.
In vertical axis washing machines, the appliance's wash basket rotates about a vertical axis. Because of the wash basket's vertical orientation, fluid within the basket can settle in the basket's sump that is positioned adjacent to a bottom of the basket. Fluid in the appliance's sump can be removed from the sump (e.g., via a pump) at the end of any particular cycle. For example, at the end of the appliance's final rinse cycle, wash fluid in the appliance's sump can be pumped out with a drain pump. However, when the drain pump shuts off, wash fluid can backflow into the sump. For example, wash fluid within the appliance's drain pipe can backflow into the sump due to gravity. The amount of wash fluid that backflows into the sump can be related to a drain pipe's height and/or orientation. However, due to such backflow, wash fluid in the sump during subsequent cycles (e.g., a steam cycle) can have an unknown composition. Such backflow can also affect the amount of wash fluid in the sump during subsequent cycles of the appliance.
Accordingly, a washing machine appliance with features for generating steam within the appliance's wash chamber would be useful. Also, a vertical axis washing machine appliance with features for generating steam within the appliance's wash chamber would be useful. In particular, a vertical axis washing machine appliance with features for controlling the composition and/or amount of fluid converted into steam within the appliance's wash chamber would also be useful.